It is commercially useful to have food service products such as plates, bowls, trays, and the like which have a shelf package presence that conveys to the consumer the key product features including style/design, color, thickness, texture and strength. Shelf package presence can be obtained through enhanced or greater height packaged product. A greater height also provides more area on the side of the package for printing the product name, description and advertising. Consistent spacing of products within each package is likewise necessary to obtain consistent package dimensions and to provide for desirable uniformity.
It is additionally desirable to have food service products which are easy to separate and dispense from the stack whether the article is a plate, bowl, tray, cup or lid and so forth. Disposable products are often produced from lower caliper materials. Spacing between products within a stack, resulting from the caliper alone would be minimal and not overcome the difficulty for the consumer to separate and dispense the product.
Spacing features have been incorporated into product design to increase and enhance the spacing between products to improve dispensability as well as to prevent so called "taperlock" wherein the sidewalls of articles are stuck together. These spacing features must be designed in such a manner that they do not nest on top of each other and thus negate their intended function. In other words, in a nested configuration of two articles, the relief patterns merely overlap each other and do not provide spacing between the articles. Spacing features, which heretofore are sometimes called "separation lugs" are often very utilitarian in nature and can detract from the overall product design and aesthetics. The present invention is directed to a method to obtain consistent, enhanced spacing on products that have symmetrical flange patterns with varying heights without using such separation lugs. The inventive patterns overcome the drawbacks of the prior art.
U.S. Pat. No. 3,672,538 to Wiedemann is directed to a disposable dish which can be stacked together with similar dishes but can easily be removed from the stack on an individual basis. The dish can be a plate, a saucer or a bowl (Col. 1, lines 13-16 and lines 57-59) and is composed of a thin sheet of a relatively rigid, semi-flexible material such as plastic, or a rigid paper (Col. 1, lines 7-9). The disposable dish has a central portion and a rim around the edge of the central portion. The rim has a plurality of special upstanding ribs which space the dishes slightly apart when the dishes are stacked together so as to facilitate separating the dishes (Col. 1, lines 39-43). The ribs are circumferentially spaced on the rim (Col. 2, lines 6-8); the rim of the dish has a pattern embossed thereon (Col. 2, lines 8-9). The ribs are part of the pattern that is larger than the other portions of the pattern as to stand up higher from the rim. When a plurality of these dishes are stacked together, the ribs engage the under surface of the rim of the next upper dish so as to slightly space the dishes apart, thereby preventing the dishes from nesting together and allowing for ease of removing individual dishes from the stack (Col. 2, lines 16-21). Preferably the ribs are non-uniformly spaced apart around the rim so as to greatly minimize the chances of the ribs on one dish meeting or fitting into the ribs of the next dish (Col. 2, lines 13-15 and lines 21-24).
U.S. Pat. No. 5,758,773 to Clements discloses molded plastic plates having a rolled edge rim, wherein the plates are premolded with lugs that project outwardly from the sides of the plate. The lugs of one plate contact the rim of the next successive plate in a stack of plates to create a gap between the plates stacked on top of one another. The gap allows the top plate in the stack to be easily picked up and separated from the remaining plates in the stack (Col. 3, lines 49-51). The lugs are spaced around the circumference of the plate (Col. 3, lines 61-62). The lugs of each successive plate are slightly offset from the corresponding lugs of the plates stacked immediately above it in order to prevent the lugs of the top plate from locking inside the lugs of the plate underneath it, thereby losing the gap between the plates (Col. 3, lines 62-66). One method of offsetting the lugs is to mold the plates from several different molds, each mold having the lug spaced at slightly different intervals (Col. 4, lines 1-4).
U.S. Pat. No. 3,931,890 to Davis is directed to disposable, thin walled, plastic lids having a stacking facility which cooperates with other similar lids to form a stable lid stack and to prevent jamming when axial loads are applied to them (Col. 1, lines 5-9). The lids are preferably formed in groups in which some of the lids of the group have projections which are of different angular spacing than the projections on other lids in the group (Col. 2, lines 23-26). Such lids are stacked in alternating sequence which ensures that the stacked lids will be mismatched and therefore will not become jammed (Col. 2, lines 26-29). The lids are designed to be made by conventional thermoforming techniques (Col. 3, lines 21-23).
U.S. Pat. No. 5,165,978 to Lecinski is directed to closure panels with flute or rib means which prevent nesting when a plurality of the closure panels (for bottle caps) are stacked (Col. 1, lines 12-15). Preferably the closure panels are formed in a multiple cavity die with each cavity having a different flute arrangement such that when the closure panels are rotated so that certain other flutes align with each other, not all flutes will be in alignment (Col. 1, lines 42-50).